1. Technical Field of the Invention
The present invention relates to an image processing device, an image processing method and a solid-state image-pickup device. In particular, the invention relates to an image processing device that reads an image signal from a matrix type solid-state image-pickup element and an image processing method and a solid-state image-pickup device thereof.
2. Description of the Related Art
A semiconductor image sensor is used for various kinds of image input devices. Recently, of such semiconductor image sensors, a MOS solid-state image-pickup device with a threshold voltage modulation system attracts attention since it provides high image quality attained by a CCD (charged coupled device) with low power consumption by a CMOS and restrains deterioration of an image quality and realizes high density and low cost.
Technology of a MOS solid-state image-pickup device with a threshold voltage modulation system is disclosed in the Japanese Patent Publication Laid-Open No. 11-195778 for example. In a MOS solid-state image-pickup device with a threshold voltage modulation system, three states such as initialization, accumulation and reading out are repeated such that an image signal based on charges for emitting light that are accumulated in a carrier pocket of each pixel can be pulled out. An initialization period is a period of discharging residual charges from a carrier pocket. An accumulation period is a period of accumulating charges in a sensor cell. A reading out period is a period of reading a volume of charge out with voltage modulation.
However, the above Japanese Patent Publication Laid-Open No. 11-195778 does not disclose the control of a line for reading out an image signal or line for clearing an image signal to attain an appropriate image output certainly without delay when conditions for picking an image up such as change of a shutter speed and others are changed.
Therefore, the present invention is intended to provide an image processing device to attain an appropriate image output without delay, an image processing method and a solid-state image-pickup device.